High-performance mount adapter for connecting M42 lenses to E-mount cameras. - Model: Turbo II M42-NEX - Type: Mount Adapter - Color: Black - Material: Metal Thank you for viewing. Purchased in October 2025. I am selling it because I no longer use it. You can use old lenses with their original focal length even on APS-C sensors :) I used it with a NEX-5T. When attached to a camera with an APS-C size sensor, you can shoot with the original angle of view ＜full size＞. The reducer lens has high light-gathering efficiency, so the F-number becomes one stop brighter. When used with a 50mm lens: 50mm * 1.5 (APS-C focal length multiplier) * 0.726 (Lens Turbo focal length multiplier) = 55mm equivalent angle of view When used with a 35mm lens: 35mm * 1.5 (APS-C focal length multiplier) * 0.726 (Lens Turbo focal length multiplier) = 38mm equivalent angle of view